diff --git a/docs/components/secure-partition-manager-mm.rst b/docs/components/secure-partition-manager-mm.rst
index 4cdb96c..d9b2b1b 100644
--- a/docs/components/secure-partition-manager-mm.rst
+++ b/docs/components/secure-partition-manager-mm.rst
@@ -4,17 +4,10 @@
 Foreword
 ========
 
-Two implementations of a Secure Partition Manager co-exist in the TF-A codebase:
-
--  SPM based on the FF-A specification (:ref:`Secure Partition Manager`).
--  SPM based on the MM interface.
-
-Both implementations differ in their architectures and only one can be selected
-at build time.
-
-This document describes the latter implementation where the Secure Partition Manager
-resides at EL3 and management services run from isolated Secure Partitions at S-EL0.
-The communication protocol is established through the Management Mode (MM) interface.
+This document describes the implementation where the Secure Partition Manager
+resides at EL3 and management services run from isolated Secure Partitions at
+S-EL0. The communication protocol is established through the Management Mode
+(MM) interface.
 
 Background
 ==========
diff --git a/docs/resources/diagrams/ffa-ns-interrupt-handling-managed-exit.png b/docs/resources/diagrams/ffa-ns-interrupt-handling-managed-exit.png
deleted file mode 100644
index 0619cf2..0000000
--- a/docs/resources/diagrams/ffa-ns-interrupt-handling-managed-exit.png
+++ /dev/null
Binary files differ
diff --git a/docs/resources/diagrams/ffa-ns-interrupt-handling-sp-preemption.png b/docs/resources/diagrams/ffa-ns-interrupt-handling-sp-preemption.png
deleted file mode 100644
index f110028..0000000
--- a/docs/resources/diagrams/ffa-ns-interrupt-handling-sp-preemption.png
+++ /dev/null
Binary files differ
diff --git a/docs/threat_model/index.rst b/docs/threat_model/index.rst
index b22fb18..3e0393e 100644
--- a/docs/threat_model/index.rst
+++ b/docs/threat_model/index.rst
@@ -31,7 +31,6 @@
    :caption: Contents
 
    threat_model
-   threat_model_spm
    threat_model_el3_spm
    threat_model_fvp_r
    threat_model_rss_interface
diff --git a/docs/threat_model/threat_model_spm.rst b/docs/threat_model/threat_model_spm.rst
deleted file mode 100644
index 24a115b..0000000
--- a/docs/threat_model/threat_model_spm.rst
+++ /dev/null
@@ -1,1340 +0,0 @@
-SPMC Threat Model
-*****************
-
-************************
-Introduction
-************************
-This document provides a threat model for the TF-A :ref:`Secure Partition Manager`
-(SPM) implementation or more generally the S-EL2 reference firmware running on
-systems implementing the FEAT_SEL2 (formerly Armv8.4 Secure EL2) architecture
-extension. The SPM implementation is based on the `Arm Firmware Framework for
-Arm A-profile`_ specification.
-
-In brief, the broad FF-A specification and S-EL2 firmware implementation
-provide:
-
-- Isolation of mutually mistrusting SW components, or endpoints in the FF-A
-  terminology.
-- Distinct sandboxes in the secure world called secure partitions. This permits
-  isolation of services from multiple vendors.
-- A standard protocol for communication and memory sharing between FF-A
-  endpoints.
-- Mutual isolation of the normal world and the secure world (e.g. a Trusted OS
-  is prevented to map an arbitrary NS physical memory region such as the kernel
-  or the Hypervisor).
-
-************************
-Target of Evaluation
-************************
-In this threat model, the target of evaluation is the S-EL2 firmware or the
-``Secure Partition Manager Core`` component (SPMC).
-The monitor and SPMD at EL3 are covered by the :ref:`Generic TF-A threat model
-<threat_analysis>`.
-
-The scope for this threat model is:
-
-- The TF-A implementation for the S-EL2 SPMC based on the Hafnium hypervisor
-  running in the secure world of TrustZone (at S-EL2 exception level).
-  The threat model is not related to the normal world Hypervisor or VMs.
-  The S-EL1 and EL3 SPMC solutions are not covered.
-- The implementation complies with the FF-A v1.0 specification, and a few
-  features of FF-A v1.1 specification.
-- Secure partitions are statically provisioned at boot time.
-- Focus on the run-time part of the life-cycle (no specific emphasis on boot
-  time, factory firmware provisioning, firmware udpate etc.)
-- Not covering advanced or invasive physical attacks such as decapsulation,
-  FIB etc.
-- Assumes secure boot or in particular TF-A trusted boot (TBBR or dual CoT) is
-  enabled. An attacker cannot boot arbitrary images that are not approved by the
-  SiP or platform providers.
-
-Data Flow Diagram
-======================
-Figure 1 shows a high-level data flow diagram for the SPM split into an SPMD
-component at EL3 and an SPMC component at S-EL2. The SPMD mostly acts as a
-relayer/pass-through between the normal world and the secure world. It is
-assumed to expose small attack surface.
-
-A description of each diagram element is given in Table 1. In the diagram, the
-red broken lines indicate trust boundaries.
-
-Components outside of the broken lines are considered untrusted.
-
-.. uml:: ../resources/diagrams/plantuml/spm_dfd.puml
-  :caption: Figure 1: SPMC Data Flow Diagram
-
-.. table:: Table 1: SPMC Data Flow Diagram Description
-
-  +---------------------+--------------------------------------------------------+
-  | Diagram Element     | Description                                            |
-  +=====================+========================================================+
-  | ``DF1``             | SP to SPMC communication. FF-A function invocation or  |
-  |                     | implementation-defined Hypervisor call.                |
-  +---------------------+--------------------------------------------------------+
-  | ``DF2``             | SPMC to SPMD FF-A call.                                |
-  +---------------------+--------------------------------------------------------+
-  | ``DF3``             | SPMD to NS forwarding.                                 |
-  +---------------------+--------------------------------------------------------+
-  | ``DF4``             | SP to SP FF-A direct message request/response.         |
-  |                     | Note as a matter of simplifying the diagram            |
-  |                     | the SP to SP communication happens through the SPMC    |
-  |                     | (SP1 performs a direct message request to the          |
-  |                     | SPMC targeting SP2 as destination. And similarly for   |
-  |                     | the direct message response from SP2 to SP1).          |
-  +---------------------+--------------------------------------------------------+
-  | ``DF5``             | HW control.                                            |
-  +---------------------+--------------------------------------------------------+
-  | ``DF6``             | Bootloader image loading.                              |
-  +---------------------+--------------------------------------------------------+
-  | ``DF7``             | External memory access.                                |
-  +---------------------+--------------------------------------------------------+
-
-*********************
-Threat Analysis
-*********************
-
-This threat model follows a similar methodology to the :ref:`Generic TF-A threat model
-<threat_analysis>`.
-The following sections define:
-
-- Trust boundaries
-- Assets
-- Theat agents
-- Threat types
-
-Trust boundaries
-============================
-
-- Normal world is untrusted.
-- Secure world and normal world are separate trust boundaries.
-- EL3 monitor, SPMD and SPMC are trusted.
-- Bootloaders (in particular BL1/BL2 if using TF-A) and run-time BL31 are
-  implicitely trusted by the usage of secure boot.
-- EL3 monitor, SPMD, SPMC do not trust SPs.
-
-.. figure:: ../resources/diagrams/spm-threat-model-trust-boundaries.png
-
-    Figure 2: Trust boundaries
-
-Assets
-============================
-
-The following assets are identified:
-
-- SPMC state.
-- SP state.
-- Information exchange between endpoints (partition messages).
-- SPMC secrets (e.g. pointer authentication key when enabled)
-- SP secrets (e.g. application keys).
-- Scheduling cycles.
-- Shared memory.
-
-Threat Agents
-============================
-
-The following threat agents are identified:
-
-- NS-Endpoint identifies a non-secure endpoint: normal world client at NS-EL2
-  (Hypervisor) or NS-EL1 (VM or OS kernel).
-- S-Endpoint identifies a secure endpoint typically a secure partition.
-- Hardware attacks (non-invasive) requiring a physical access to the device,
-  such as bus probing or DRAM stress.
-
-Threat types
-============================
-
-The following threat categories as exposed in the :ref:`Generic TF-A threat model
-<threat_analysis>`
-are re-used:
-
-- Spoofing
-- Tampering
-- Repudiation
-- Information disclosure
-- Denial of service
-- Elevation of privileges
-
-Similarly this threat model re-uses the same threat risk ratings. The risk
-analysis is evaluated based on the environment being ``Server`` or ``Mobile``.
-
-Threat Assessment
-============================
-
-The following threats are identified by applying STRIDE analysis on each diagram
-element of the data flow diagram.
-
-+------------------------+----------------------------------------------------+
-| ID                     | 01                                                 |
-+========================+====================================================+
-| ``Threat``             | **An endpoint impersonates the sender or receiver  |
-|                        | FF-A ID in a direct request/response invocation.** |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3, DF4                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMD, SPMC                                         |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP state                                           |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Spoofing                                           |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------++----------------+---------------+
-| ``Impact``             | Critical(5)      | Critical(5)     |               |
-+------------------------+------------------++----------------+---------------+
-| ``Likelihood``         | Critical(5)      | Critical(5)     |               |
-+------------------------+------------------++----------------+---------------+
-| ``Total Risk Rating``  | Critical(25)     | Critical(25)    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC does not mitigate this threat.       |
-|                        | The guidance below is left for a system integrator |
-|                        | to implemented as necessary.                       |
-|                        | The SPMC must enforce checks in the direct message |
-|                        | request/response interfaces such an endpoint cannot|
-|                        | spoof the origin and destination worlds (e.g. a NWd|
-|                        | originated message directed to the SWd cannot use a|
-|                        | SWd ID as the sender ID).                          |
-|                        | Additionally a software component residing in the  |
-|                        | SPMC can be added for the purpose of direct        |
-|                        | request/response filtering.                        |
-|                        | It can be configured with the list of known IDs    |
-|                        | and about which interaction can occur between one  |
-|                        | and another endpoint (e.g. which NWd endpoint ID   |
-|                        | sends a direct request to which SWd endpoint ID).  |
-|                        | This component checks the sender/receiver fields   |
-|                        | for a legitimate communication between endpoints.  |
-|                        | A similar component can exist in the OS kernel     |
-|                        | driver, or Hypervisor although it remains untrusted|
-|                        | by the SPMD/SPMC.                                  |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 02                                                 |
-+========================+====================================================+
-| ``Threat``             | **Tampering with memory shared between an endpoint |
-|                        | and the SPMC.**                                    |
-|                        | A malicious endpoint may attempt tampering with its|
-|                        | RX/TX buffer contents while the SPMC is processing |
-|                        | it (TOCTOU).                                       |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF3, DF4, DF7                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | Shared memory, Information exchange                |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering                                          |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | High (4)         | High (4)        |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | High (4)         | High (4)        |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | High (16)        | High (16)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | In context of FF-A v1.0 and v1.1 this is the case  |
-|                        | of sharing the RX/TX buffer pair and usage in the  |
-|                        | PARTITION_INFO_GET or mem sharing primitives.      |
-|                        | The SPMC must copy the contents of the TX buffer   |
-|                        | to an internal temporary buffer before processing  |
-|                        | its contents. The SPMC must implement hardened     |
-|                        | input validation on data transmitted through the TX|
-|                        | buffer by an untrusted endpoint.                   |
-|                        | The TF-A SPMC mitigates this threat by enforcing   |
-|                        | checks on data transmitted through RX/TX buffers.  |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 03                                                 |
-+========================+====================================================+
-| ``Threat``             | **An endpoint may tamper with its own state or the |
-|                        | state of another endpoint.**                       |
-|                        | A malicious endpoint may attempt violating:        |
-|                        | - its own or another SP state by using an unusual  |
-|                        | combination (or out-of-order) FF-A function        |
-|                        | invocations.                                       |
-|                        | This can also be an endpoint emitting              |
-|                        | FF-A function invocations to another endpoint while|
-|                        | the latter is not in a state to receive it (e.g. a |
-|                        | SP sends a direct request to the normal world early|
-|                        | while the normal world is not booted yet).         |
-|                        | - the SPMC state itself by employing unexpected    |
-|                        | transitions in FF-A memory sharing, direct requests|
-|                        | and responses, or handling of interrupts.          |
-|                        | This can be led by random stimuli injection or     |
-|                        | fuzzing.                                           |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3, DF4                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMD, SPMC                                         |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP state, SPMC state                               |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering                                          |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | High (4)         | High (4)        |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | High (12)        | High (12)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC provides mitigation against such     |
-|                        | threat by following the guidance for partition     |
-|                        | runtime models as described in FF-A v1.1 EAC0 spec.|
-|                        | The SPMC performs numerous checks in runtime to    |
-|                        | prevent illegal state transitions by adhering to   |
-|                        | the partition runtime model.                       |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 04                                                 |
-+========================+====================================================+
-| ``Threat``             | *An attacker may attempt injecting errors by the   |
-|                        | use of external DRAM stress techniques.**          |
-|                        | A malicious agent may attempt toggling an SP       |
-|                        | Stage-2 MMU descriptor bit within the page tables  |
-|                        | that the SPMC manages. This can happen in Rowhammer|
-|                        | types of attack.                                   |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF7                                                |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP or SPMC state                                   |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | Hardware attack                                    |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering                                          |
-+------------------------+------------------+---------------+-----------------+
-| ``Application``        |   ``Server``     |  ``Mobile``   |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Impact``             | High (4)         | High (4)	    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Likelihood``         | Low (2)          | Medium (3)    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Total Risk Rating``  | Medium (8)       | High (12)	    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Mitigations``        | The TF-A SPMC does not provide mitigations to this |
-|                        | type of attack. It can be addressed by the use of  |
-|                        | dedicated HW circuity or hardening at the chipset  |
-|                        | or platform level left to the integrator.          |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 05                                                 |
-+========================+====================================================+
-| ``Threat``             | **Protection of the SPMC from a DMA capable device |
-|                        | upstream to an SMMU.**                             |
-|                        | A device may attempt to tamper with the internal   |
-|                        | SPMC code/data sections.                           |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF5                                                |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC or SP state                                   |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering, Elevation of privileges                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Application``        |   ``Server``     |  ``Mobile``   |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Impact``             | High (4)         | High (4)      |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Total Risk Rating``  | High (12)        | High (12)     |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Mitigations``        | A platform may prefer assigning boot time,         |
-|                        | statically alocated memory regions through the SMMU|
-|                        | configuration and page tables. The FF-A v1.1       |
-|                        | specification provisions this capability through   |
-|                        | static DMA isolation.                              |
-|                        | The TF-A SPMC does not mitigate this threat.       |
-|                        | It will adopt the static DMA isolation approach in |
-|                        | a future release.                                  |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 06                                                 |
-+========================+====================================================+
-| ``Threat``             | **Replay fragments of past communication between   |
-|                        | endpoints.**                                       |
-|                        | A malicious endpoint may replay a message exchange |
-|                        | that occured between two legitimate endpoint as    |
-|                        | a matter of triggering a malfunction or extracting |
-|                        | secrets from the receiving endpoint. In particular |
-|                        | the memory sharing operation with fragmented       |
-|                        | messages between an endpoint and the SPMC may be   |
-|                        | replayed by a malicious agent as a matter of       |
-|                        | getting access or gaining permissions to a memory  |
-|                        | region which does not belong to this agent.        |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF2, DF3                                           |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | Information exchange                               |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Repdudiation                                       |
-+------------------------+------------------+---------------+-----------------+
-| ``Application``        |   ``Server``     |  ``Mobile``   |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Impact``             | Medium (3)       | Medium (3)    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Likelihood``         | High (4)         | High (4)	    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Total Risk Rating``  | High (12)        | High (12)     |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Mitigations``        | The TF-A SPMC does not mitigate this threat.       |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 07                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint may attempt to extract data |
-|                        | or state information by the use of invalid or      |
-|                        | incorrect input arguments.**                       |
-|                        | Lack of input parameter validation or side effects |
-|                        | of maliciously forged input parameters might affect|
-|                        | the SPMC.                                          |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3, DF4                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMD, SPMC                                         |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP secrets, SPMC secrets, SP state, SPMC state     |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Information discolure                              |
-+------------------------+------------------+---------------+-----------------+
-| ``Application``        |   ``Server``     |  ``Mobile``   |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Impact``             | High (4)         | High (4)      |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Total Risk Rating``  | High (12)        | High (12)     |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Mitigations``        | Secure Partitions must follow security standards   |
-|                        | and best practises as a way to mitigate the risk   |
-|                        | of common vulnerabilities to be exploited.         |
-|                        | The use of software (canaries) or hardware         |
-|                        | hardening techniques (XN, WXN, BTI, pointer        |
-|                        | authentication, MTE) helps detecting and stopping  |
-|                        | an exploitation early.                             |
-|                        | The TF-A SPMC mitigates this threat by implementing|
-|                        | stack protector, pointer authentication, BTI, XN,  |
-|                        | WXN, security hardening techniques.                |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 08                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint may forge a direct message  |
-|                        | request such that it reveals the internal state of |
-|                        | another endpoint through the direct message        |
-|                        | response.**                                        |
-|                        | The secure partition or SPMC replies to a partition|
-|                        | message by a direct message response with          |
-|                        | information which may reveal its internal state    |
-|                        | (.e.g. partition message response outside of       |
-|                        | allowed bounds).                                   |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3, DF4                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC or SP state                                   |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Information discolure                              |
-+------------------------+------------------+---------------+-----------------+
-| ``Application``        |   ``Server``     |  ``Mobile``   |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Impact``             | Medium (3)       | Medium (3)    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Likelihood``         | Low (2)          | Low (2)	    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Total Risk Rating``  | Medium (6)       | Medium (6)    |                 |
-+------------------------+------------------+---------------+-----------------+
-| ``Mitigations``        | For the specific case of direct requests targeting |
-|                        | the SPMC, the latter is hardened to prevent        |
-|                        | its internal state or the state of an SP to be     |
-|                        | revealed through a direct message response.        |
-|                        | Further, SPMC performs numerous checks in runtime  |
-|                        | on the basis of the rules established by partition |
-|                        | runtime models to stop  any malicious attempts by  |
-|                        | an endpoint to extract internal state of another   |
-|                        | endpoint.                                          |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 09                                                 |
-+========================+====================================================+
-| ``Threat``             | **Probing the FF-A communication between           |
-|                        | endpoints.**                                       |
-|                        | SPMC and SPs are typically loaded to external      |
-|                        | memory (protected by a TrustZone memory            |
-|                        | controller). A malicious agent may use non invasive|
-|                        | methods to probe the external memory bus and       |
-|                        | extract the traffic between an SP and the SPMC or  |
-|                        | among SPs when shared buffers are held in external |
-|                        | memory.                                            |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF7                                                |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP/SPMC state, SP/SPMC secrets                     |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | Hardware attack                                    |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Information disclosure                             |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Low (2)          | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (6)       | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | It is expected the platform or chipset provides    |
-|                        | guarantees in protecting the DRAM contents.        |
-|                        | The TF-A SPMC does not mitigate this class of      |
-|                        | attack and this is left to the integrator.         |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 10                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious agent may attempt revealing the SPMC |
-|                        | state or secrets by the use of software-based cache|
-|                        | side-channel attack techniques.**                  |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF7                                                |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP or SPMC state                                   |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Information disclosure                             |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Low (2)          | Low (2)         |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (6)       | Medium (6)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | From an integration perspective it is assumed      |
-|                        | platforms consuming the SPMC component at S-EL2    |
-|                        | (hence implementing the Armv8.4 FEAT_SEL2          |
-|                        | architecture extension) implement mitigations to   |
-|                        | Spectre, Meltdown or other cache timing            |
-|                        | side-channel type of attacks.                      |
-|                        | The TF-A SPMC implements one mitigation (barrier   |
-|                        | preventing speculation past exeception returns).   |
-|                        | The SPMC may be hardened further with SW           |
-|                        | mitigations (e.g. speculation barriers) for the    |
-|                        | cases not covered in HW. Usage of hardened         |
-|                        | compilers and appropriate options, code inspection |
-|                        | are recommended ways to mitigate Spectre types of  |
-|                        | attacks. For non-hardened cores, the usage of      |
-|                        | techniques such a kernel page table isolation can  |
-|                        | help mitigating Meltdown type of attacks.          |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 11                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint may attempt flooding the    |
-|                        | SPMC with requests targeting a service within an   |
-|                        | endpoint such that it denies another endpoint to   |
-|                        | access this service.**                             |
-|                        | Similarly, the malicious endpoint may target a     |
-|                        | a service within an endpoint such that the latter  |
-|                        | is unable to request services from another         |
-|                        | endpoint.                                          |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3, DF4                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Denial of service                                  |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (9)       | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC does not mitigate this threat.       |
-|                        | Bounding the time for operations to complete can   |
-|                        | be achieved by the usage of a trusted watchdog.    |
-|                        | Other quality of service monitoring can be achieved|
-|                        | in the SPMC such as counting a number of operations|
-|                        | in a limited timeframe.                            |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 12                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint may attempt to allocate     |
-|                        | notifications bitmaps in the SPMC, through the     |
-|                        | FFA_NOTIFICATION_BITMAP_CREATE.**                  |
-|                        | This might be an attempt to exhaust SPMC's memory, |
-|                        | or to allocate a bitmap for a VM that was not      |
-|                        | intended to receive notifications from SPs. Thus   |
-|                        | creating the possibility for a channel that was not|
-|                        | meant to exist.                                    |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3                                      |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Denial of service, Spoofing                        |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium(3)        | Medium(3)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium(3)        | Medium(3)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium(9)        | Medium(9)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC mitigates this threat by defining a  |
-|                        | a fixed size pool for bitmap allocation.           |
-|                        | It also limits the designated FF-A calls to be used|
-|                        | from NWd endpoints.                                |
-|                        | In the NWd the hypervisor is supposed to limit the |
-|                        | access to the designated FF-A call.                |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 13                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint may attempt to destroy the  |
-|                        | notifications bitmaps in the SPMC, through the     |
-|                        | FFA_NOTIFICATION_BITMAP_DESTROY.**                 |
-|                        | This might be an attempt to tamper with the SPMC   |
-|                        | state such that a partition isn't able to receive  |
-|                        | notifications.                                     |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3                                      |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering                                          |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Low(4)           | Low(4)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC mitigates this issue by limiting the |
-|                        | designated FF-A call to be issued by the NWd.      |
-|                        | Also, the notifications bitmap can't be destroyed  |
-|                        | if there are pending notifications.                |
-|                        | In the NWd, the hypervisor must restrict the       |
-|                        | NS-endpoints that can issue the designated call.   |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 14                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint might attempt to give       |
-|                        | permissions to an unintended sender to set         |
-|                        | notifications targeting another receiver using the |
-|                        | FF-A call FFA_NOTIFICATION_BIND.**                 |
-|                        | This might be an attempt to tamper with the SPMC   |
-|                        | state such that an unintended, and possibly        |
-|                        | malicious, communication channel is established.   |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3                                      |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering, Spoofing                                |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium(3)        | Medium(3)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium(6)        | Medium(6)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC mitigates this by restricting        |
-|                        | designated FFA_NOTIFICATION_BIND call to be issued |
-|                        | by the receiver only. The receiver is responsible  |
-|                        | for allocating the notifications IDs to one        |
-|                        | specific partition.                                |
-|                        | Also, receivers that are not meant to receive      |
-|                        | notifications, must have notifications receipt     |
-|                        | disabled in the respective partition's manifest.   |
-|                        | As for calls coming from NWd, if the NWd VM has had|
-|                        | its bitmap allocated at initialization, the TF-A   |
-|                        | SPMC can't guarantee this threat won't happen.     |
-|                        | The Hypervisor must mitigate in the NWd, similarly |
-|                        | to SPMC for calls in SWd. Though, if the Hypervisor|
-|                        | has been compromised, the SPMC won't be able to    |
-|                        | mitigate it for calls forwarded from NWd.          |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 15                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious partition endpoint might attempt to  |
-|                        | set notifications that are not bound to it.**      |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3                                      |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Spoofing                                           |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Low(4)           | Low(4)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC mitigates this by checking the       |
-|                        | sender's ID provided in the input to the call      |
-|                        | FFA_NOTIFICATION_SET. The SPMC keeps track of which|
-|                        | notifications are bound to which sender, for a     |
-|                        | given receiver. If the sender is an SP, the        |
-|                        | provided sender ID must match the ID of the        |
-|                        | currently running partition.                       |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 16                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious partition endpoint might attempt to  |
-|                        | get notifications that are not targeted to it.**   |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3                                      |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Spoofing                                           |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Informational(1) | Informational(1)|               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC mitigates this by checking the       |
-|                        | receiver's ID provided in the input to the call    |
-|                        | FFA_NOTIFICATION_GET. The SPMC keeps track of which|
-|                        | notifications are pending for each receiver.       |
-|                        | The provided receiver ID must match the ID of the  |
-|                        | currently running partition, if it is an SP.       |
-|                        | For calls forwarded from NWd, the SPMC will return |
-|                        | the pending notifications if the receiver had its  |
-|                        | bitmap created, and has pending notifications.     |
-|                        | If Hypervisor or OS kernel are compromised, the    |
-|                        | SPMC won't be able to mitigate calls from rogue NWd|
-|                        | endpoints.                                         |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 17                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious partition endpoint might attempt to  |
-|                        | get the information about pending notifications,   |
-|                        | through the FFA_NOTIFICATION_INFO_GET call.**      |
-|                        | This call is meant to be used by the NWd FF-A      |
-|                        | driver.                                            |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3                                      |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Information disclosure                             |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium(3)        | Medium(3)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium(6)        | Medium(6)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC mitigates this by returning error to |
-|                        | calls made by SPs to FFA_NOTIFICATION_INFO_GET.    |
-|                        | If Hypervisor or OS kernel are compromised, the    |
-|                        | SPMC won't be able mitigate calls from rogue NWd   |
-|                        | endpoints.                                         |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 18                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious partition endpoint might attempt to  |
-|                        | flood another partition endpoint with notifications|
-|                        | hindering its operation.**                         |
-|                        | The intent of the malicious endpoint could be to   |
-|                        | interfere with both the receiver's and/or primary  |
-|                        | endpoint execution, as they can both be preempted  |
-|                        | by the NPI and SRI, respectively.                  |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3, DF4                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state, SP state, CPU cycles                   |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | DoS                                                |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Low(2)           | Low(2)          |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium(3)        | Medium(3)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium(6)        | Medium(6)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC does not mitigate this threat.       |
-|                        | However, the impact is limited due to the          |
-|                        | architecture:                                      |
-|                        | - Notifications are not queued, one that has been  |
-|                        | signaled needs to be retrieved by the receiver,    |
-|                        | until it can be sent again.                        |
-|                        | - Both SRI and NPI can't be pended until handled   |
-|                        | which limits the amount of spurious interrupts.    |
-|                        | - A given receiver could only bind a maximum number|
-|                        | of notifications to a given sender, within a given |
-|                        | execution context.                                 |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 19                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint may abuse FFA_RUN call to   |
-|                        | resume or turn on other endpoint execution         |
-|                        | contexts, attempting to alter the internal state of|
-|                        | SPMC and SPs, potentially leading to illegal state |
-|                        | transitions and deadlocks.**                       |
-|                        | An endpoint can call into another endpoint         |
-|                        | execution context using FFA_MSG_SEND_DIRECT_REQ    |
-|                        | ABI to create a call chain. A malicious endpoint   |
-|                        | could abuse this to form loops in a call chain that|
-|                        | could lead to potential deadlocks.                 |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF4                                      |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC, SPMD                                         |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state, SP state, Scheduling cycles            |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering, Denial of Service                       |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (9)       | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC provides mitigation against such     |
-|                        | threats by following the guidance for partition    |
-|                        | runtime models as described in FF-A v1.1 EAC0 spec.|
-|                        | The SPMC performs numerous checks in runtime to    |
-|                        | prevent illegal state transitions by adhering to   |
-|                        | the partition runtime model. Further, if the       |
-|                        | receiver endpoint is a predecessor of current      |
-|                        | endpoint in the present call chain, the SPMC denies|
-|                        | any attempts to form loops by returning FFA_DENIED |
-|                        | error code. Only the primary scheduler is allowed  |
-|                        | to turn on execution contexts of other partitions  |
-|                        | though SPMC does not have the ability to           |
-|                        | scrutinize its identity. Secure partitions have    |
-|                        | limited ability to resume execution contexts of    |
-|                        | other partitions based on the runtime model. Such  |
-|                        | attempts cannot compromise the integrity of the    |
-|                        | SPMC.                                              |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 20                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint can perform a               |
-|                        | denial-of-service attack by using FFA_INTERRUPT    |
-|                        | call that could attempt to cause the system to     |
-|                        | crash or enter into an unknown state as no physical|
-|                        | interrupt could be pending for it to be handled in |
-|                        | the SPMC.**                                        |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF5                                      |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC, SPMD                                         |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state, SP state, Scheduling cycles            |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering, Denial of Service                       |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (9)       | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC provides mitigation against such     |
-|                        | attack by detecting invocations from partitions    |
-|                        | and simply returning FFA_ERROR status interface.   |
-|                        | SPMC only allows SPMD to use FFA_INTERRUPT ABI to  |
-|                        | communicate a pending secure interrupt triggered   |
-|                        | while execution was in normal world.               |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 21                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious secure endpoint might deactivate a   |
-|                        | (virtual) secure interrupt that was not originally |
-|                        | signaled by SPMC, thereby attempting to alter the  |
-|                        | state of the SPMC and potentially lead to system   |
-|                        | crash.**                                           |
-|                        | SPMC maps the virtual interrupt ids to the physical|
-|                        | interrupt ids to keep the implementation of virtual|
-|                        | interrupt driver simple.                           |
-|                        | Similarly, a malicious secure endpoint might invoke|
-|                        | the deactivation ABI more than once for a secure   |
-|                        | interrupt. Moreover, a malicious secure endpoint   |
-|                        | might attempt to deactivate a (virtual) secure     |
-|                        | interrupt that was signaled to another endpoint    |
-|                        | execution context by the SPMC even before secure   |
-|                        | interrupt was handled.                             |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF5                                           |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state, SP state                               |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | S-Endpoint                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering                                          |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (9)       | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | At initialization, the TF-A SPMC parses the        |
-|                        | partition manifests to find the target execution   |
-|                        | context responsible for handling the various       |
-|                        | secure physical interrupts. The TF-A SPMC provides |
-|                        | mitigation against above mentioned threats by:     |
-|                        |                                                    |
-|                        | - Keeping track of each pending virtual interrupt  |
-|                        |   signaled to an execution context of a secure     |
-|                        |   secure partition.                                |
-|                        | - Denying any deactivation call from SP if there is|
-|                        |   no pending physical interrupt  mapped to the     |
-|                        |   given virtual interrupt.                         |
-|                        | - Denying any deactivation call from SP if the     |
-|                        |   virtual interrupt has not been signaled to the   |
-|                        |   current execution context.                       |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 22                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious secure endpoint might not deactivate |
-|                        | a virtual interrupt signaled to it by the SPMC but |
-|                        | perform secure interrupt signal completion. This   |
-|                        | attempt to corrupt the internal state of the SPMC  |
-|                        | could lead to an unknown state and further lead to |
-|                        | system crash.**                                    |
-|                        | Similarly, a malicious secure endpoint could       |
-|                        | deliberately not perform either interrupt          |
-|                        | deactivation or interrupt completion signal. Since,|
-|                        | the SPMC can only process one secure interrupt at a|
-|                        | time, this could choke the system where all        |
-|                        | interrupts are indefinitely masked which could     |
-|                        | potentially lead to system crash or reboot.        |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF5                                           |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state, SP state, Scheduling cycles            |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | S-Endpoint                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Tampering, Denial of Service                       |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (9)       | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC does not provide mitigation against  |
-|                        | such threat. This is a limitation of the current   |
-|                        | SPMC implementation and needs to be handled in the |
-|                        | future releases.                                   |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 23                                                 |
-+========================+====================================================+
-| ``Threat``             | **A malicious endpoint could leverage non-secure   |
-|                        | interrupts to preempt a secure endpoint, thereby   |
-|                        | attempting to render it unable to handle a secure  |
-|                        | virtual interrupt targetted for it. This could lead|
-|                        | to priority inversion as secure virtual interrupts |
-|                        | are kept pending while non-secure interrupts are   |
-|                        | handled by normal world VMs.**                     |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3, DF5                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC, SPMD                                         |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state, SP state, Scheduling cycles            |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint                                        |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Denial of Service                                  |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (9)       | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC alone does not provide mitigation    |
-|                        | against such threats. System integrators must take |
-|                        | necessary high level design decisions that takes   |
-|                        | care of interrupt prioritization. The SPMC performs|
-|                        | its role of enabling SPs to specify appropriate    |
-|                        | action towards non-secure interrupt with the help  |
-|                        | of partition manifest based on the guidance in the |
-|                        | FF-A v1.1 EAC0 specification.                      |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 24                                                 |
-+========================+====================================================+
-| ``Threat``             | **A secure endpoint depends on primary scheduler   |
-|                        | for CPU cycles. A malicious endpoint could delay   |
-|                        | the secure endpoint from being scheduled. Secure   |
-|                        | interrupts, if not handled timely, could compromise|
-|                        | the state of SP and SPMC, thereby rendering the    |
-|                        | system unresponsive.**                             |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2, DF3, DF5                                 |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC, SPMD                                         |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state, SP state, Scheduling cycles            |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint                                        |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Denial of Service                                  |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (9)       | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC does not provide full mitigation     |
-|                        | against such threats. However, based on the        |
-|                        | guidance provided in the FF-A v1.1 EAC0 spec, SPMC |
-|                        | provisions CPU cycles to run a secure endpoint     |
-|                        | execution context in SPMC schedule mode which      |
-|                        | cannot be preempted by a non-secure interrupt.     |
-|                        | This reduces the dependency on primary scheduler   |
-|                        | for cycle allocation. Moreover, all further        |
-|                        | interrupts are masked until pending secure virtual |
-|                        | interrupt on current CPU is handled. This allows SP|
-|                        | execution context to make progress even upon being |
-|                        | interrupted.                                       |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 25                                                 |
-+========================+====================================================+
-| ``Threat``             | **A rogue FF-A endpoint can use memory sharing     |
-|                        | calls to exhaust SPMC resources.**                 |
-|                        | For each on-going operation that involves an SP,   |
-|                        | the SPMC allocates resources to track its state.   |
-|                        | If the operation is never concluded, the resources |
-|                        | are never freed.                                   |
-|                        | In the worst scenario, multiple operations that    |
-|                        | never conclude may exhaust the SPMC resources to a |
-|                        | point in which renders memory sharing operations   |
-|                        | impossible. This could affect other, non-harmful   |
-|                        | FF-A endpoints, from legitimately using memory     |
-|                        | share functionality. The intent might even be      |
-|                        | to cause the SPMC to consume excessive CPU cycles, |
-|                        | attempting to make it deny its service to the NWd. |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2                                           |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC, SPMD                                         |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SPMC state                                         |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Denial of Service                                  |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | High (4)         | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | High (4)         | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | High (16)        | Medium (9)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC uses a statically allocated pool of  |
-|                        | memory to keep track of on-going memory sharing    |
-|                        | operations. After a possible attack, this could    |
-|                        | fail due to insufficient memory, and return an     |
-|                        | error to the caller. At this point, any other      |
-|                        | endpoint that requires use of memory sharing for   |
-|                        | its operation could get itself in an unusable      |
-|                        | state.                                             |
-|                        | Regarding CPU cycles starving threat, the SPMC     |
-|                        | doesn't provide any mitigation for this, as any    |
-|                        | FF-A endpoint, at the virtual FF-A instance is     |
-|                        | allowed to invoke memory share/lend/donate.        |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 26                                                 |
-+========================+====================================================+
-| ``Threat``             | **A borrower may interfere with lender's           |
-|                        | operation, if it terminates due to a fatal error   |
-|                        | condition without releasing the memory             |
-|                        | shared/lent.**                                     |
-|                        | Such scenario may render the lender inoperable.    |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2                                           |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC                                               |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP state                                           |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Denial of Service                                  |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | High (4)         | Low (2)         |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | High (12)        | Medium(6)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC does not provide mitigation for such |
-|                        | scenario. The FF-A endpoints must attempt to       |
-|                        | relinquish memory shared/lent themselves in        |
-|                        | case of failure. The memory used to track the      |
-|                        | operation in the SPMC will also remain usuable.    |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 27                                                 |
-+========================+====================================================+
-| ``Threat``             | **A rogue FF-A endpoint may attempt to tamper with |
-|                        | the content of the memory shared/lent, whilst      |
-|                        | being accessed by other FF-A endpoints.**          |
-|                        | It might attempt to do so: using one of the clear  |
-|                        | flags, when either retrieving or relinquishing     |
-|                        | access to the memory via the respective FF-A       |
-|                        | calls; or directly accessing memory without        |
-|                        | respecting the synchronization protocol between    |
-|                        | all involved endpoints.                            |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2                                           |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC, FF-A endpoint                                |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP state                                           |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Denial of Service, Tampering                       |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | Low (2)          | Low (2)         |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Medium (3)      |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | Medium (6)       | Medium(6)       |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The first case defined in the threat, the TF-A     |
-|                        | SPMC mitigates it, by ensuring a memory is cleared |
-|                        | only when all borrowers have relinquished access   |
-|                        | to the memory, in a scenario involving multiple    |
-|                        | borrowers. Also, if the receiver is granted RO,    |
-|                        | permissions, the SPMC will reject any request      |
-|                        | to clear memory on behalf of the borrower, by      |
-|                        | returning an error to the respective FF-A call.    |
-|                        | The second case defined in the threat can't be     |
-|                        | mitigated by the SPMC. It is up to the NS/S FF-A   |
-|                        | endpoints to establish a robust protocol for using |
-|                        | the shared memory.                                 |
-+------------------------+----------------------------------------------------+
-
-+------------------------+----------------------------------------------------+
-| ID                     | 28                                                 |
-+========================+====================================================+
-| ``Threat``             | **A rogue FF-A endpoint may attempt to share       |
-|                        | memory that is not in its translation regime, or   |
-|                        | attempt to specify attributes more permissive than |
-|                        | those it possesses at a given time.**              |
-|                        | Both ways could be an attempt for escalating its   |
-|                        | privileges.                                        |
-+------------------------+----------------------------------------------------+
-| ``Diagram Elements``   | DF1, DF2                                           |
-+------------------------+----------------------------------------------------+
-| ``Affected TF-A        | SPMC, FF-A endpoint                                |
-| Components``           |                                                    |
-+------------------------+----------------------------------------------------+
-| ``Assets``             | SP state                                           |
-+------------------------+----------------------------------------------------+
-| ``Threat Agent``       | NS-Endpoint, S-Endpoint                            |
-+------------------------+----------------------------------------------------+
-| ``Threat Type``        | Denial of Service, Tampering                       |
-+------------------------+------------------+-----------------+---------------+
-| ``Application``        |   ``Server``     |   ``Mobile``    |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Impact``             | High (4)         | Low (2)         |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Likelihood``         | Medium (3)       | Low (2)         |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Total Risk Rating``  | High (12)        | Low (2)         |               |
-+------------------------+------------------+-----------------+---------------+
-| ``Mitigations``        | The TF-A SPMC mitigates this threat by performing  |
-|                        | sanity checks to the provided memory region        |
-|                        | descriptor.                                        |
-|                        | For operations at the virtual FF-A instance, and   |
-|                        | once the full memory descriptor is provided,       |
-|                        | the SPMC validates that the memory is part of the  |
-|                        | caller's translation regime. The SPMC also checks  |
-|                        | that the memory attributes provided are within     |
-|                        | those the owner possesses, in terms of             |
-|                        | permissiveness. If more permissive attributes are  |
-|                        | specified, the SPMC returns an error               |
-|                        | FFA_INVALID_PARAMETERS. The permissiveness rules   |
-|                        | are enforced in any call to share/lend or donate   |
-|                        | the memory, and in retrieve requests.              |
-+------------------------+----------------------------------------------------+
-
---------------
-
-*Copyright (c) 2021-2023, Arm Limited. All rights reserved.*
-
-.. _Arm Firmware Framework for Arm A-profile: https://developer.arm.com/docs/den0077/latest
-.. _FF-A ACS: https://github.com/ARM-software/ff-a-acs/releases
-